This invention relates generally to centrifugal pumps and more particularly to multi-stage centrifugal pumps.
Captured casing rings and bushings are normally found in horizontally split pumps such as a single stage double suction pump and multi-stage volute pumps. Channel ring bushings are usually shrunk fit into a channel ring or diffuser and then locked in position with set screws drilled and tapped on the joint line, with large head screws in a milled recess, welded in place or bolted in place. Replacement of this part can be difficult in the field. Particularly if radiation is involved. Contaminated parts have to be ground or machined for removal, releasing airborne contamination. The bolted in part partially solves this problem, but it is large and can not be used on channel ring bushings in a compact design.
Typically, channel rings use an interference fit with the pump casing to retain the channel rings in place. Because of the interference fit, these channel rings are difficult to remove. Disassembly can be a time consuming operation.
The foregoing illustrates limitations known to exist in present multi-stage centrifugal pumps. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.